Lowering your blood pressure is smart if your readings are inching too high. But lowering it too much might actually hurt your heart, too, new research from Johns Hopkins suggests.

In the study of over 11,000 people, adults with diastolic blood pressure readings (the bottom number when you get your BP tested) under 60 millimeters of mercury (mm Hg) were 49 percent more likely to suffer a heart event, such as a heart attack, than those with diastolic BP between 80 to 89.

They were also 32 percent more likely to die of any cause over 20 years.

The researchers aren’t sure what caused the link, but they did discover that those with diastolic BP under 60 mm Hg also tended to have tiny concentrations of a certain heart muscle protein in their bloodstream.

The protein indicates that there’s been reduced blood flow to your coronary arteries, which can damage your heart muscle, says researcher John William McEvoy, M.B.B.Ch., M.H.S.

You probably only need to worry about low diastolic BP if you have other heart issues like blocked arteries or systolic BP above 140 mm Hg, Dr. McEvoy says.

That’s because those issues can compound the heart-damaging effects of low diastolic BP, making a heart event more likely.

So if you’re on blood pressure meds to reduce your high blood pressure, work with your doctor to make sure he or she is monitoring your levels regularly. If reducing your systolic BP is dropping your diastolic blood pressure too low, he or she can tinker with the dose of your heart meds until you reach a happy medium.